(a) Field of the Invention
The present invention relates to a thin film transistor (TFT), a TFT array panel, and a method of manufacturing the TFT array panel.
(b) Description of the Related Art
There are two types of silicon depending on their crystal state. One is amorphous silicon and the other is crystalline silicon.
Amorphous silicon is popularly used to form semiconductors of TFTs employed in a display device using a glass substrate with a relatively low melting point. This is because amorphous silicon can be thinly deposited on the substrate at a low temperature.
However, amorphous silicon has a problem of low electric mobility. Because of such a problem, it may be unsuitable to apply it to semiconductors of large size display devices.
The problem of the low electric mobility can be overcome by using polycrystalline silicon instead of amorphous silicon. Polycrystalline silicon has good electrical characteristics, such as high electric mobility, better performance in a high frequency operation, and less leakage current.
Polycrystalline silicon is commonly obtained by laser annealing of amorphous silicon such as excimer laser annealing technology or sequential lateral solidification technology. Accordingly, process cost for the display panel increases. Also, in this case, it is difficult to obtain polycrystalline silicon with uniform crystallinity over the entire display panel.